I believe I did the same thing. I just cut the transom down a bit.When I glued on the sheer strake there was a good half inch extra at the stern. I trimmed it off without thinking but now I realize that it doesn't come up far enough and too much of the transom is sticking out above the plank. Annoying, but there isn't much I can do about it so I guess I just move on and write it off as a learning experience.